Tillman is a step up for All Black Williams, who has faced four carefully selected fighters for four easy victories in his professional boxing career. Tillman, a former professional footballer who weighs about 127kg and stands 1.96m tall, beat Tutaki in a split decision last year.
He said he was aware of the residency issue and accepted it. "That doesn't matter to me,'' he said. "I would give the title up. There are guys here who deserve it.''
The New Orleans-born Tillman, who has a professional record of 11 wins, eight losses and two draws from his 21 bouts, settled in Auckland after travelling to the city for a fight against Junior Pati in 2010.
"I'm gonna beat the hell out of this dude [Williams],'' Tillman said. "He can't fight, he doesn't know what he's doing. I saw his last fight with Alipate [Liava'a].
"He was throwing punches and he was spinning around, turning his back. Like, who does that? When they told me that they chose me [as his next opponent], I felt disrespected almost. I was actually surprised that he was going to fight Tutaki. I think Richard would have beaten him or at least gone really close.''
Tillman, who had been training to fight former league player Solomon Haumono in Australia when he was given the option of the Williams fight, said he was in good shape.
"I haven't done this much running since my football days,'' he said.